The earbuds use an active noise-cancelling or canceling technology to reduce external or background noise rendering a particularly suitable and relaxing listening atmosphere in areas with shrill background sonance. You don’t find this ANC is normal headphones. With noise cancelling circuitry, the earbuds, the electronics built into the earpiece creates a loop which is 180° enabling it to eliminate background sound.
This loop acts as a sound eliminator, canceling unwanted from around you without interfering with audio output from the earbud or audio giving you a clear a well-deserved music or movie listening. The microphone uses a miniature microphone in the earbud that picks up background sonance.